Mineral-concentrator.



c. 0. a; w. MIGHAELSEN. MINERAL CONCENTRATOR. APPL-ICATIOHFILED SEPT. 7. 1916.

1,269,,1 98., f Patented June 11, 1918.

*' 7S.HEET$$HEET 1- Wm. & Chas. 0. Michael sepjJweM Com 7 SHEETS-SHEET 2- c 0. & Wu P. MICHAELSEN.

MINERAL CONCENTRATOR.

APPLICATION FILED SEPT, 1. 191a. I 1 269 198 Patented June 11. 1918.

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W dow 00 C. O. 6; W. P. MlCHAELSEN.

MINERAL CONCENTRATOR.

APPLICATION FILED SEPT, 2. 1916.

1,269,190 I Patented June 11, 191 8.

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C. U. 64 W. P. MiCHAELSEN MINERAL CONCENTRATOR.

APPLICATION HLED SEPT, 7, \916.

Patented June 11, 1918.

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- MINERAL CONCENTRATOR.

APPLICATION men sen 7. I916.

1,269,]L 98. 1 Patenfgrd Jmw 11, 1918.

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MWERAL CONCENTRATOR.

APPHCATXON FILED SEPTJ. i916- 1,2693 98. Batontmil June/11, 1918.

ISHtETSSHEET I.

Ch z is. Michaelsen, lwuewbow. .g Wm. P. Michaelsen.

' both of Minneapolis, in the county of materials of the .lowing is e ens CHARLES OsMIGHAELSEN AND WILLIAM P. MICHAELSEN, OF MINNEAPOLIS, MINNE- SOTA, assrenons 'ro inrcnnntsnn'm Havana rarnnnan-concnn'rnaron.

' Specification of Letters Patent. Patented June 11, 1918.

Application filed September 7, 1916. Serial No. 118533.

To all whom. it may concern .Be it known that we, CHARLES 0. MI-

GHA'ELSEN and WILLIAM P. Mrorramfinu,

nepin and State of Minnesota, have invented certain new and useful Improvements'in Mineral-Concentrators, of which the fola specification. Our invention relates to mineral concentrators for use in separating the valuable vention are to provide regulatable means for continuously feeding materials to the machine; to provide a separation-pan oscillate.-

, ble about avertical axis and into which the materials are fed at the peripheral portion thereof; rovide actuating means for rapidly oscil ating said pan to provide means forming a waste-discharge opening at the upper central portion of the pan; to provide meansat the peripheral portion of the pan for either continuously or intermittently discharging the concentrates; to provide means, forming an opening at the lower central part of the pan for discharging partially-concentrated material; to' provide means for returning said partially-concentrated material to the peripheral part of the pan; to provide regulatable' means forstirring or agitating and loosening the solid materials in the pan so as to keep the same in partial suspension in the water or washin medium therein; to provide means for su merging slimes and finely divided mate- .rial containing valuable matter so that the latter will pass beneath a blanket 0r suspended layer of waste matter and pass 06 with theother concentrates; and to provide various other particular constructions and combinations of mechanism, which will be hereinaftenfully set forth. In the accompanying drawings Figure 1.

is a partialplon view of a machine embodying our'invention, Fig. 2 is a transverse vertical sectional view of the same, Fig. 3 is a longitudinal vertical sectional view thereof, Fig. 4 is a detail transverse vertical section, showing the central portion of the machine on a. larger scale than in Fig. 2, Fig. 5 is a detail vertical section through the drivingkhead of one of the siderrods, Fig. 6 is a detail horizontal section through the other head of said rod, Fig. 7 is a detail plan View of one of the pan-centering andsupporting devices,.Fig. 8 is a detail verticalsection on the plane of the line 8-8 of Fi J 7 Fig. 9 isa detail vertical section throng the elevating pump mechanism, Fig. 10 isa detail transverse section on the plane of the acnmnm COMPANY, A conroaarron' or line 10-10 of Fig. 9, Fig. 11 is a detail vertical section through one of the concen} trates-discharge valves, Fig. 12 is a section of the same, on the diagonal plane of the line 12-12 of Fig. 11, Fig. 13 is a detail vertical section of ayportion of the pan, showing the means for vertically adjusting the submersion-ring, and Fig. 14: is a detail vertical sectional view showing the distributionof material in the pan when the machine is in operation. In the illustrated embodiment of our in? vention we provide a main frame consisting principally of parallel side-members 20 and cross-members 21 extending transversely between the'ends thereof and rigidly secured thereto. The side-members have foot-portions 22 whichrest upon a suitable base or foundation and at one end have bracket-like portions 23 extending beyond the adjacent cross-member. On the upper sides of'said bracket-portions are secured bearings 24' in which is journaled the main driving-shaft 25. On said shaft, between the bearings, there is mounted a pulley 26 which is connected by belt with a suitable source of power. 'Fly wheels 27 are mounted on the shaft ad oining the outer ends of the bearings 24, and outside the fly-wheels there are,v

secured eccentrics 28 which are employed, as hereinafter described, for actuating the oscillating pa At one end the shaft.25 carries a small cone-step pulley 29, from which the upper or cross-shaft is driven, as will'appear below.

' 'On the upper side'of each of the frame side-members 20, at the intermediateportion thereof, there are securedvthe foot-portions of a bracket 30 having approximately the so: I

form of an inverted To the upper portions of the brackets 30 are secured the ends of the cross-beani 31. and on said cross-beam are mounted bearings 32 and 33 in which is iournaled the cross-shaft i-rt one end said cross-shaft carries cone-step pulley which is connected with the pulley 29 by means of a belt 36.

At each of the four corners formed by the juncture oi? the frame members and 21. there secured on the upper sides thereor one of the angleplates 3'? shown in de tail in rigs. 7 and 8. Each of the anglesecured therein a stud 39 which extends in horizontally and has revolubly mounted thereon roller 40. Said rollers l0 form the supporting means for the oscillating separation-pan, the axes of: the rollers ex 20 tending radially to the pan and the same being movable about a Vertical axis. The n'iargin or outer rim all of the separation pan has an inwMilly-extending lip at its upper edge, and from said lip the rim tends downwardly, sloping inward slightly, and at its lower edge merges into a rounded portion 4E3 which is the bottom of an annular trough or channel. The inner side of the annular trough is formed by an "upwardly inclined or sloping portion. 44- which. rises to a height somewhat less than half tr e height of the outer rim above the. bottom of the trough. The inner edge of the riortion merges into the margin of conical downwardly and inwardly in- -clined part. which slopes gently toward the center or vertical axis oi the pan. The part e5 terminates at a downward offset or shoulder which forms the rim of a cen tral poclnt or howl. of which the bottom 47 extends in at the same inclination as the part do and ends at the edge of a circular central oning; through the bottom of the pan. iiithin said central opening there is arranger a seat-ring which is preferably made oi a hard non-corrosihle and wearresisting material such as hionel metal. The seat-ring is retained in the opening by of a a9 secured to the bottom of the pan by screws 50, said ring; having a cylindrical downwarally-extending at the inner thereof, as sin vn. (in the lo-werside the rounded part tl ere are p'lane suriiaced boss ii. to which are secured nard wearing-plates Said plates upon the rollers which sustain the so that it may hare a rotational nent in a horizontal olanc about its otical The pan is centered. or reant inst lateral movenr hy the .ol-

the outer side oiithc are bosses or pifijfitlln por- "ev'ng cylindro-scgniental surfaces or material. Each of the plates at its inner side a lug 38 having secured arcuate wetting ngle-plates 37 has an upwardly extending rangeportion with 1nwardly-extending as at the ends thereof, and between said ugs there is held a block 57 of which the inner face is adapted to fit against and form a hearing for the wearing-plate 5r on the adjacent boss 53 of the pan. The bearingblocks are held by screws 58 extended through the lugs 56, and may be adjusted radially of the pan by means of screws 59 extending through the flange-portions and engaging the blocks, as shown.

At opposite sides of the pan, beneath the cross-beam, there ar projecting lugs 60 on the rim ii, and onto said lugs are'fitted and secured the flanged base-portions of arms 61 which e-Xtei d laterally therefrom andcarry at their ends cylindrical heads 62. Said arms til pass out through the spaces between the tootportions of thehrackets 80 which supgort the cross-beam and the heads 69. are 7 located outside of said brackets as indicated in Fig. The eccentrics -28 on the main. driving shaft are connected yieldingly with the heads by means of side-rods of which the detailed construction is shown in Figs. 5 and 6. Arounrheach or the eccentrics 28 there is titted two-part box consisting of 63 and 64 Within Wlnchthe eccentric parts is rcvoluble. The box-part 63 s retained within a U-shaped head or yoke 65 by means of screws 66, and the bOXPZ lf t 64 has pIOJeCting lugs at its upper and tower sides which fit against the end of the yolre and are secured thereto byscrews 67. At the other end of the yoke there is a projecting por tion which fits between the upper and lower parts of a forked head 68', the same being pirotally connected with the yoke by aver tically-eirteuding pin 69 passing through the parts as shown. in linto the neckpoi ion of the head there is screwed the end of a rod 70 said. rod extendin horizontally therefrom and passing loosely through the central opening 01: the head 62 at the respective side otthe pan. Coil springs 71 and 72 are disposed around the rod at 0pposite sides of the head 62, the ends of the springs resting in recesses in the ends otjthe head. The springs areh'eld under a certain. compression by collars 73 and 7%., which are screwedon threaded portions of the rod eccentrics are arranged with their centers on' opposite sides of the axis of the shaft 25, so that the in. veinents imparted thereby to oscillatory movements movement.

tion of the driving eccentrics is slow enough the side-rods are equal and opposite in direction. During rotation of' the shaft 25 the eccentrics cause, of course, certain oscillatory movements of the side-rods in avertical plane, but the openings through the heads 62 are large enough-to permit such movement without causing binding or swinging of the parts. Themovements of the siderods cause oscillatory movements of the separation-pan about the vertical axis thereof,

and, as the heads 62 are moved in arcuate paths about the axis of the pan, there are caused slight lateral movements of the siderods. The joint formed by the pin 69 between the head 68 and yoke 65 permits such lateral movements to be made without cansin bindingof the box-parts on the eccentrio. If both of thesprings 71 and 72 are the same at both sides of the machine, the of the pan will be alike in each direction, but the extent of the movements will vary slightly according to the strength of the springs and the rate of Thus, when the rate of rotaso that the inertia of the pan can be overcome without causing increased compression of the springs either in starting or stopping, the extent of movement will be the same as the throw of the eccentrics. But when the rateof rotation of the eccentrics exceeds a certain limit, then in overcoming the inertia of the pan at the limits of movement thereof the springs will be compressed beyond their normalor initial compression, and-the extent of the movements imparted to the'pan will no longer correspond exactly to the throw of the eccentrics. A further modification of the movement may be effected by making the opposing springs of difi'erent flexibility. Thus, if the spring 71 at one side of the machine, and the spring 72 at the other side, are more flexible than the re spectively opposed springs, the movements of the pan in one direction will be stopped more abruptly than the movements in the opposite direction; the more abrupt stopping belng effected at the end of the stroke at which the movement is opposed by the stifi'er springs. The described modification of the simple harmonic oscillatory -movement is made use of for a purpose which will appear hereinafter.

To .the rim of the pan, on top of the lip 42, there aresccured the ends of a plurality of L-shaped arms 78 which extend radialliy inward, the angle-portions thereof depen ing vertically angle-portions having vertically-elongated openings therein, as best shown in Fig. 13. To said arms 7 8 the submersion-ring 79 is secured b ring and t ring being pan, and with e slots in the arms, as shown, the thereby held concentric witlrthe its lower edge extending into at the inner ends, and said bolts 80 passing through thethe inner ortion of the annular trough. The

' the valved discharge-spouts 82, shown in detail in Figs. -11 and 12. In each of the spout-bodies there is a cylindrical opening extending parallel with the face of the boss 81, and in said opening is disposed a tubular bushing 83 within which a valve-body 8ifits revolubly. The bushing and valvebody terminate near the inclined bottomportion of the spout, and the valve-body has in its lower end a transverse slot adapted to register with a slot 85 that extends through the inner side of the bushing 83 and continues through the'pan-portion l3 to the lower and outer portion of the annular trough. The valves may beturned so as to stop oii the passages through the slots 85, or to open the same to any extent desired. At the center of the cross-beam 31 there is a large'circular opening through which is extended a vertical bearing 86 formed I integrally with a plate 87 which rests on' top of the cross-beam and is secured thereto by bolts 88. In the'bearing 86 there is revolubly disposed a tubular shaft 89 having at its upper end an integral flange-portion 90. I Between the flange-portion 90 and the plate 87 an annular ball-thrust-bearing 91 is arranged as shown. The ball-thrustbearing is surrounded by a flange 92, integral with the .plate 87, and forming a receptacle for the retention of a lubricant for the bearing, supplied from an oil-cup 93 arranged below the plate 87 as shown clearly in Fig. l. To the flange 90 of the tubular shaft-there is secured a bevel gear 94 which meshes with a bevel pinion 95 secured on the cross-shaft 34 so as to be driven therefrom. The lower end-portion of the tubular shaft 89 is threaded to receive the upper end-portion of a cylindrical shell 96, which isscrewed thereon and held in fixed relation thereto by set-screws 97 The lowerend of'the shell 96 extends into proximity screw 116 arranged as shown.

A rod 106 extends slidahly through the tubular shaft 89, and the upper end of said rod 106 is connected with a two-part rectangular yoke-107, the of which on gage slidably the sides of a bearinghloelr 108 mounted on the raft as, as shown. A screw 109 extends through. a threaded vertical opening in the upper end-portion of the yoke 107, the lower end of the screw having an annular flange 110 which fits revolubly in a. soclrctplate 111 secured on the upper side of the bearingbloelr 1108. Alt the upper end otthe screw 109 a spoked hand-wheel 112 is secured thereon, so that the screw may be turned by means of said wheel. 0n the portion of the screw 109 above the yoke there is a loclrnut 113 screwed thereon, said locknut being integral with and forming the hub-portion of a spolred hand-wheel 11 1. By suitable manipulation. of the two hand-wheels, the yoke 10'? and rod 106 may be raised and lowered, and secured in adjusted relations to the crossshaft and bearing-block 108. At the lower end of the rod 106 the same has a threaded portion on which is screwed the upper part of'a cylindrical shell 115, the same being held in fixed relation to rod by a setl'n the sides of the shell 115 are series of ports 11'? correspondingto the ports 98 in the shell is an inwardly- 96, and below the ports there extending conular lip 118. llie lower end of the shell 115 has secured thereon a valvering 119 adapted to seat against the ring 18 to stop oil' the opening through the same,

and by the above described raising and lowering of the rod 106 any desired width of opening may be established between the rings'119 and The portion of the shell 115 below the ports 11? is slightly larger in diameter than theportion containing said ports, and there are provided a. series of shouldered stop-rings 120 which fit slidably on said ported portion of the shell. The shouldered ends of thestop-rings overlap each other when fitted together, as shown.

clearly in Fig. i, and said rings are eniplo'yed to stop off the lower portions of the poi-tell? to raise the level at which'fluid materials in the separation-pan can flow through said ports to the inside of the shell. When the stop-rings not in use for the their upper described purpose, they are raised up into the upper part of the outer shell 96,-and held in said raised position by means of screws 3321 extended through the sides of said shell, as shown. Below the ports 98 and 117 a packing-ringlQfZ is arranged so as to fill and stop oil" the annular space be tween the shells 96 and115.

Materials flowing from the pan inwardly through the ports 98 and 117, pass down within the shell 115 and are directed by the conular lip 118 into the upper end of a dischargepipe 123. Said pipe passes through the seat-ring -18 and flanged-ring49 concentrically therewith but in spaced relation to the sides thereof, so that an annular opening is left around. the pipe for the escape of materials which flow between therings 18 and 119. Such materials are directed by the depending flange of the ring 49 into the which surrounds the pipe 1.23and has a. dischargeoutlet 1-25 at one-side thereof. Thefunnel 12% has a flanged base-portion which rests upon and is secured to the central part of an arched cross-beam 1'26, the ends of said cross-learn beingsupported on the lower horizontal portions of the frame side-memberg 20. The pipe 123 has an integral annular flange 127 which fits against and is secured to the base-portion of the funnel.

The outlet or discharge-spout 125 of the funnel empties into the upper portion of an inclined trough or chute 128 which extends diagonally to the sump-casing 129 of an elevating pump mechanism which is ar ranged at the same end of the machine as the main driving shaft 25. Said sump-easing 129 is integral with the chute 128, andhas thereina ll-shaped passage communicating at one side with the lower end of the chute, as shown in Fig. 9. At the upper ends of the Ushaped passage the casing has sockets in which are fitted the lower ends of pipes 130 and 131 which-extend upwardly therefrom, passing on opposite sides of the drivingshaft Said pipes at ends it into sockets in the headcasing 132, and the casings 129 and 132 are secured to each other by long bolts 133 which extend alongside the pipes and are connected with flanges at the sides of the sockets. The

head-casing 132 has a removable cover 133%,

justable vertically by means of screws 141) 5 which pass through flanges at the-loiedge of the casingand engage the lower per tions of the bearings rece es as shown in Figs; 9

' and 10, On one end of the shaft 137 there is secured. a small pulley .141 which is connected by a belt 142 with a pulley 143 on the main shaft 25, so as to be driven therefrom.

An endless chain 14A passes over the wheel 136, extendingtherefrom down pipe 130, through the" U-shaped passage of I the sump-caslng 129,- and up through the pipe 131 to the wheel. On said chain at suitable intervals there are secured plungers 145 adapted to fit within the pipes, so that when the chain is moved by rotation of the wheel materials will be carried up throu h the pipe 131 from the sump-casing to t. e'

head casing, and discharged therefrom through the spout 135.

d To the intermediate portions of the frame cross-members 21 there are secured pairs of bracket-arms 146 which extend upward and diagonally outward therefrom; past the adjacent marginal portions of the separationpan, and to the upper portions of each pair of said arms is secured one of the feedhoppers 147. The lower ends of said hoppers have nozzle-like portions 148 which extend down into the annular trough-portion of the pan, openlng toward the rim 411, as shown. Materials elevated by the pump mechanism are discharged by the spout 135 into one of said feed-hoppers, and other materials are supplied thereto as hereinafter set forth. In the ends-of each hopper there are bearings for a shaft 149 which extends horizontally through hopper 1 and carries a series of agitating-paddles 150 on the intermediate portion thereof. The shafts 149 carry at one end pulleys 151 which are connected by belts 152 with pulleys 153 mounted on the cross-shaft 3 1 adjoining. the bearings 33, the arrangement being such that the agitator-shafts 149 are driven-from the cross-shaft in the directions indicated in Fig. 3. In each hopper, below the agitating-paddles, there is arranged a plate 154.- which extends slidably through the inner side of the hopper and which has on the lower side thereof rack-bars I155 meshing with inions 156 carried on a shaft 157 extending liorizontally beneath the plate at the side of the hopper. The shafts 157 are journaled in suitable bearings at the ends of the hoppers, and. each shaft has at one end a hand-wheel 158 by which it may be turned to move the respective plate 15 through the medium of the pinions and rack-bars. -The plates 154; are, in effect,

valves which enable regulation of the flow of material from the feed-hoppers to the separation-pan.

Besides the materials supplied to the machine through the feed-hoppers, there may be supplied thereto limited quantities of water, as followsz-At the shoulder 46 of the an there is secured therein an an le-rin thro ughth? bowl-portion of the pan,

159 which incloses an annular space between the same and the bottom of the pan.

A pipe 160 1s screwed into an openingun' the bottom of the pan communlcating with ply pipe 162 is connected with'one side of the funnel 124, as shown in Figs. 2 and 4,;

and water supplied through said pipe is employed for flushing solid material out of the funneh The detailed operation of the described mechanism is varied accord ng to the class of material being handled thereby. To attain the most satisfactory results in a machine proportioned as shown inthe drawlugs, and in which the'diameter of the separation-pan is about 60 inches, the main drive-shaft should be driven at. a speed of 250 to 300 revolutions per minute, and the extent of the oscillatory movement of the gun at the marginal ortion thereof should e about one inch. he springs 71 and 72 are preferably proportioned as hereinbefore mentioned, sothat' the movement of the pen in one direction will be stopped more abruptly than the movements in the other direction,'as by this means the oscillatory movements have a terials around the pan in the direction of the movements which terminate most abruptly. 'The' rate of movement of the cross-shaft 34:, from which are driventhe rotary agitating arms carried by the shell 96, is varied as required, by placing the belt 36 on difierent portions of the cone-steptendenoy to work the mapulleys 29 and 35. Variation of the rate of movement of the cross-shaft 3a causes a similar variation of the rate of movement of the agitating devices in the feed-hoppers. The rate of movement of the elevating pump mechanism is always proportional to the speed of the main drive-shaft 25, the mechanism being so proportioned that at such speed the pump will have ample capacity to raise the maximum required volume of material.

When first commencing the operation'of the machine, the central part 'ofthe pan is .filled with clean sand to of the ports 117 as-determined by the stop r1ngs'120, and the annular trough-portin of the pan is also filled to a level" above the the overflow; level valves 8st are closed; and

so the valve-plates an edge of the rim,

50 non-metalliferous I so the bottom of the annular trough.

lower edge of the submersionaing 79. The shell 115 is lowered, by manipulation of the hand-wheels 112 and 11st, to stop oil the opening between the rings 48 and 119; the the pan is'lilled overflow. level. Power is then applied to the main drive-shaft, and the shaking or oscillation of the pan, together With the agitation caused by the with Water to the to movement of the rotary arms 101, 102, 103,

104iand 105, causes the sand to be kept in suspension in the Water, so that the pan is filled with a semi-fluid mixture of sand and water, the consistency of which may be de 15 scribed as approximately that of quicksand.

causes this. semi- The rotational movement fluid material to pile up more or less toward the outer edge or rim 41, so that the surface of the material in the annular trough-portion or the pan is inclined inwardly approximately as indicated at A in Fig. 14. After the described preparation, or priming J3- erations, the placer sand, or the crushed and pulverized ore containing the valuable min eral tobe recovered, is supplied to the feed:

hoppers together with a suitable quantity of Water, and the feeding of said material from the hoppers to the pan is regulated as desired, by adjustment of the positions of its the material from the feed-hoppers passes therefrom through the nozzle-portionsllS into the annular trough-portion of the pan, said material is directed by the nozzle-portions against the rim 41 and quickly becomes distributed with 45 be shaken in a horizontal plane by the oscil:

latory movements of the pan, and said shaking or agitation of the material causes the heavier metalliferons portions thereof to be gin to settle and pass beneath the lighter portions, so that a large proportion of the valuable mineral constituents of the ore pass almost immediately to the bottom of the annular trough. Besides the settling or gravitational movement of the heavy material there is a slight centrifugal. action, due to the rotational component of the oscillatory movei'ient, which causes the portions of greatest .specific gravity to tend to accumulate toward the outer part of The incoming materials from the feed-hoppers gradually displace the sand and Water with Which the pan isfilled at thebeginning of the operation, and said priming materials pass inwardly toward th center out the pan,

eventually reaching the ports 11 and flowing through the same to the waste-pipe 123. As the priming sand is displaced, however, the waste material from the ore constantly replaces the same, so that during the operation of the machine the body of the pan is constantly tilled to the overflow level with a semi-fluid mass or blanket of loose granular solid material suspended or partially suspended in Water.

After the feeding of the ore has been commenced and continued for a. time such that the material lying against the bottom 13 of I the annular trough consists almost entirely of valuable i'nineral constituents, the valves St are opened slightly so as to feed off said material through the slots 85 and spouts 82 at a rate equal to that at which said constituents are being separated from the ore.

In some cases, as where a very small proportion of the mineral is being separated, the concentrates may be discharged by opening the valves 8% intermittently.

A certain portion or the 'aluable constituents of the ore will, of course, mss inwardly from the annular trough, over the crest formed at the juncture of the pan-portions ll and l5, and on in toward the center of the pan. Such valuable material, however, being heavier than the Waste material, will constantly tend to descend through the mass of Waste material and will eventually reach the surface or" the painbody, thence passing along the bottom thereof toward the center. After the operation of the machine has been continued long enough for some of said valuable mineral constituents to have reached the central bowl-portion of the pan, the shell 115 is raised slightly so as to afford an opening between the valvcring 119 and seat-ring 48, and thereafter a constant flow oi material is permitted through said opening, the extent of which is so regulated that the material thus drawn oil will include all of the valuable mineral constituents of the ore except such as have been retained in the an nular trough. The material drawn oil through the bottom opening of the pan will include, of course, a considerable proportion of Waste material, but as "all of said material is returned by the elevating pump mecha-- nism to one of the feed-hoppers, there will be no loss of the valuable constituents. Thus, by suit-ably regulating the operation of tee mae; the valuable constituents of the ore may be obtained at the spouts 82 substantially unmixed with any waste matter, and the Waste matter discharged through the pipe li23entirely freed from any valuable constituents The submersiona'ing 79 has an important tun .ion in the operation, by preventing the admission of any material to the central part of the pan directly from the surface-portion of the material in the outer part of the anill) nular trough. Theflower edge of the ring being constantly submerged, it is obvious that all the material that enters the"central portion of the pan must become submerged in passing beneath said lower edge of the ring. Now in certain classes of ores a considerable part of the mineral values are found in a state of minute subdivision and are mixed with waste material which is also finely divided, and said materials when mixed with water form slimes which will float on the surface of the material, holding .the mineral values in suspension and tend ing to prevent the separationthereof from the waste matter. We have found, however, that when such slimy material is once'submerged, seas to pass beneath the surface of the befiore-mentioned blanket of sus pended sand or waste material, the mineral values thereof are separable from the waste in the same manner as the coarser values,

, and will pass to the bottom of'the pan so as to be recoverable directly with the coarser values.

For use of the/machine in recovering the values from placer sands and crushed and pulverized free-milling ores, wherein all the values are in the form of amalga-mable metallic particles, the discharge-valves 84: may

be closed and a quantity of quicksilver disposed in the annular trough-portion of the.

pan. In said quicksilver the valuable metallic particles will amalgamate as the same are brought into contact therewith, while sand and valueless material will be washed away and eventually pass ofi'through the central wastepipe 123. Any valuable :ma-

, terial that escapesamalgamation when first introduced into the pan, will descend to the bottom of the pan in passing in toward the center thereof, and will be drawn 0d at the.

bottom-opening between .the rings 48 and being mixed 119, thence passing to the elevating pump and being thereby returned to the feed-hopper so as tobe again subject to amalgamation. W' hen the machine is operated in this manner, it is stopped at suitable intervals and a clean-up made of the amalgam, as

usual in amalgamation processes.

It may be noted that under; average conditions of operation about 75% of the valuable material fed to the annular trough will be immediately retained therein; that the remainder of the valuable material may be recovered at thccentral bottom-opening of the Pan n a partially-concentrated condition,

with a certain proportion of waste matter; and that, when-the machine is properly adjusted and operated in accordance with the characteristics'jof the material-handled, there is a constant elimination of'waste matter at the upper central opening of the pan through the ports 98 and 117.

By the employment in the one machine of what may be designated as a primary and asecondary separation pi condentration of the materials, it'is possible toso regulate the operation that the primary concentrates are substantially clean and unmixed-with anywaste material, without danger of. ultimate loss of any valuable material, as all of such material lost in the primary separation may be recovered in the secondary separation, and in the product of the latter asuflicient quantity ofwaste matter may be included to insure the retention of all values.

Now, having described our invention, what we claim and desire to secure-by Letters Patent isz. 1. In a mineral mounted to oscillate about a vertical axis, said pan having an annular trough disposed pan sloping inwardly and downwardly from concentrator, a pair marginally thereofv and thebottom, of the the inner edge of said 'annular trough, means 35 for feeding materials into said annular trough, means forming a discharge-outlet from the bottom of said annular trough, means forming two outletsfrom the paIiZa-t the. central part thereof, one of saidoutlets so being at a higher level than the other, and means for receiving materials. from the lower of said outlets and returning the same to the annular trough. V v

2. In 'a mineral concentrator, a circular pan mounted to oscillate horizontally about a fixed vertical axis, said pan having a con-- cave central portion terminating marginally in a crest concentric with the pan-rim, and a concave-bottomed annular trough between said crest and rim, means-forming a wastedischarge passage opening to the central part of the pan above the bottom thereof,

means forming 'a central discharge-opening. at the lowermost bottom-portion of the pan, means for-elevating and conveying materials from the latter" discharge-opening to the ana continuousbafile-ring supported from the upper part of the outer rim and disposed concentrically; therewith and so as to dip into the annular trough to a level belowjthe inner margin thereof, and. means for iieed-,

ing materials into the trough between the.

outer rim and thebafiie-ring, whereby said materials pass beneath the submerged lower edge of the ring before flowing onto the conical pan-portion. 1

4. in a machine of the-class described a horizontally disposed pan mounted to oscillate about a vertical axis, said pan having an annular conical concave portion,'an axial member, sweep -arms connected with said member and having portions movable in the annular trough, means for feeding materials into the trough so that the same will flow therefrom inwardly over the surface of the conical portion, a discharge-pipe extending through the bottom-opening or the pan in spaced relation to the edges of said opening, a tubular valve-member disposed around the upper portion of the discharge-pipe and adapted to stop-off the opening around said pipe through the bottom of the pan, means extending up from said valve-member through the tubular rotary member and connecting with the cross-shaft to support the valve-member therefrom, and means for varying the relation of said connecting means and the cross-shaft to raise and lower the valve-member and vary the extent of the opening around the discharge-pipe.

5. in a n chine of the class described, a l'iorizontallp sposcd pan comprising an annular trough having a substantially cylindri cal outer rim, and a relatively conical body-portion sloping inwardly and downwardly from the inner margin of the annular trough, said inner margin of the trough being lower than the outer rim whereby fluid materials placed in the trough will fill the same to the level or said margin.

and then flow inwardly over said margin and down the sloping body-portion toward the center of the pan, a continuous battlering arranged to dip Within the annular trough and extend below the level of inner margin thereof, means for feeding materials into the trough outside the hit. le ring, whereby said materials must pass oeneath said ring in flowing to the inner margin of the trou h, means for agitating ma-' terialswithin the pan, means forming an annular discharge opening at the, central lowermost portion of the pan, and means forn'iing a discharge passage at the center of the pan and opening thereto at a higher level than that of the first-named discharge passage.

ti. in a mineral concentrator", an oscilla-- tory separation pan having'a marginal depression and a central depression, means for feeding materials into the marginal portion of the pan, means torcontrolling overflow of materials from said marginalportion into the central portion, means for discharging concentrates from the bottom of the marginal depression, means for discharging waste material from the upper part of the central portion of the pan, means for discharging partially-concentrated material from the bottom of the central depression, and means for returning said partially-concentrated n'iaterials to the marginal portion of the pan.

7. In a mineral-concentrator, in combination, primary separation means comprising. an oscillatory receptacle, means for feeding materials thereto, means for discharging concentratesifil'rom the bottom tl'iereof, and means "for k" trolling a marginal overflow of materials crefrom; secondary separation means comprising a receptacle receiving the overflow from the primary receptacle, for agitating said i'naterials, means for discharging partially-concentrated materials from the bottom thereof, and means for discharging waste material at a level above that for discharging the partiallyctmcentratod materials; and means for returning the partially-concentrated matcrials to the primary separation means to be rehandlcd therein.

CHARLES o. r/ncnarmsnn. vvr Mara r. nrcnannsnn 

